J/\(psi\) production as a function of charged-particle pseudorapidity density in p-Pb collisions at \(\sqrt{s_{\rm NN}} = 5.02\) TeV

Abstract

We report measurements of the inclusive J/\(\psi\) yield and average transverse momentum as a function of charged-particle pseudorapidity density \({\rm d}N_{\rm ch}/{\rm d}\eta\) in p-Pb collisions at \(\sqrt{s_{\rm NN}}= 5.02\) TeV with ALICE at the LHC. The observables are normalised to their corresponding averages in non-single diffractive events. An increase of the normalised J/\(\psi\) yield with normalised \({\rm d}N_{\rm ch}/{\rm d}\eta\), measured at mid-rapidity, is observed at mid-rapidity and backward rapidity. At forward rapidity, a saturation of the relative yield is observed for high charged-particle multiplicities. The normalised average transverse momentum at forward and backward rapidities increases with multiplicity at low multiplicities and saturates beyond moderate multiplicities. In addition, the forward-to-backward nuclear modification factor ratio is also reported, showing an increasing suppression of J/\(\psi\) production at forward rapidity with respect to backward rapidity for increasing charged-particle multiplicity.